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## Finding length of 3D line when given end points.

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### #1 Anonymous Poster_Anonymous Poster_*   Guests

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Posted 25 August 1999 - 09:20 PM

Anyone know how to calculate the length of a line in 3D when you know the endpoints.

Like (x1, y1, z1) and (x2, y2, z2).

Thanks!

### #2mutex  Members

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Posted 25 August 1999 - 07:00 PM

here's C++:

float x = x1 - x2;
float y = y1 - y2;
float z = z1 - z2;

distance = sqrt(x*x + y*y + z*z)

### #3 Anonymous Poster_Anonymous Poster_*   Guests

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Posted 25 August 1999 - 07:22 PM

Thanks for your quick response Mutex.

### #4Pryankster  Members

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Posted 25 August 1999 - 09:20 PM

Remember, however, that for many applications of the distance function (checking for collisions against bounding spheres, etc). You can usually get away with using the "distance squared", and avoid doing the (SLOW!) square-root operation.

i.e.: if you have two billiard balls which are 2 units in diameter, to see if they collide, you can check to see if their centers are within 4 units of each other, avoiding a square root operation.

-- Pryankster

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